Many emerging communication network services require interworking of several administration domains, such as IP and Ethernet based Virtual Private Networks (VPNs) spanning the domains of multiple service providers. Configuration and operation of these cross-domain services (whether across administrations, technologies, or multi-vendor network equipment) requires the exchange of service information between disparate systems. Since different domains address provisioning issues in different ways (such as address assignment and bandwidth allocation), the domains cannot establish the service simply and consistently.
Network management infrastructures are currently characterized as technology or service specific management application stacks or silos, each domain being managed by a separate individual domain manager. In order to provide cross-domain services, an overlay of workflow mechanisms is typically used for coordinating cross-domain management processes. This is in effect a manual configuration of the service, a costly and burdensome system integration activity. The services are implemented as business-to-business solutions, each service being effectively manually provisioned after negotiations between the domain administrators, such as the service providers and the long haul backbone operators.
An automated signaling mechanism would allow cross-domain services to be established more quickly and at a lower cost. Automated signaling mechanisms have been used in the network control plane in the various dedicated technology domains (for example, PNNI for ATM network), but have so far shown little progress and adoption beyond intra-domain use. In particular, such signaling mechanisms have failed to support generalized signaling by failing to clearly address key management aspects such as cross domain link connection management and fault correlation, localization, and recovery.
One common architecture for compensating the shortcomings and limited applicability of this automated signaling mechanism at the network control plane is a centralized, hierarchically layered network management architecture that spans many different elements in order to allow cross-domain provisioning and management signaling. However, such a centralized solution will scale poorly, especially as network services become more complex and dynamic, and is typically focused on a single vendor. A centralized solution is equivalent to a cascading set of workflows, and its architecture fundamentally has the same issues. These solutions typically involve several layers of OSS management systems, each layer being built and open to upper layers in an ad-hoc manner. These solutions may use, for example, integration bus technologies such as a publish-subscribe infrastructure. A key shortcoming of these integrations is that they are specific to certain equipment, technology, and even network service. The message content that is exchanged by the many systems is therefore limited to specific services, technologies, and equipment, lacking flexibility to adapt to new services. Therefore, the intelligence added to a Network Element in order to enable a centralized solution is oriented to provide local correlation and aggregation of events and notifications that will be consumed by the upper, hierarchically arranged layer. A centralized solution is costly, since it does not address reduction of complexity and tends to create vertical solutions since the servers providing the solution are provided on a per service basis. The solution is directly connected to the network element infrastructure in which they are deployed, thereby determining their vertical nature and resulting in sub-optimal use of the infrastructure, fragmentation of management control, and top heavy management.
A solution which provided a degree of automation for provisioning and managing cross-domain services would move implementation of such services away from implementations that use business-to-business technologies in ad-hoc manners and towards a network management layer implementation. A solution which provided an architecture which distributed this automated signaling mechanism across domains would be dynamic and flexible, and therefore less costly and more useful than a centralized approach, in light of the fact that centralized solutions are not easy to adapt to new cross-domain services.